Piston compressor for compressing gas

摘要

A horizontal piston compressor having at least one first cylinder end (3), a piston (10), a piston rod passage (7) and a piston rod (30) being connected to a reciprocating piston (10) and extending through the piston rod passage (7), a stuffing box (50) arranged at the first cylinder end (3) that the piston rod (30) extends there through and that comprise one or more packing rings (51) engaging the piston rod (30) and providing a seal therewith, a piston rod external surface liquid cooling system with a piston rod cooling unit (60) arranged adjacent to a side of the one or more packing rings (51). Cooling liquid passes through a cooling liquid supply channel to an annular space (77) between the ring member (75) and the piston rod (30). Buffer gas seals (105) being provided in the piston rod cooling unit (60) delimiting an annular buffer gas space (104) at each axial end of the annular space (77). The cooling unit (60) is provided with one or more buffer gas supply channels (102) to supply a buffer gas thereto, the cooling system comprising a source (100) of pressurized buffer gas for establishing a buffer gas pressure in each buffer gas space (104).